1. Field of the Invention
The invention relates in general to hydraulic jacks, and more specifically to shipping assemblies for protecting the hydraulic cylinder and plunger of a hydraulic jack during shipment.
2. Description of the Prior Art
Hydraulic elevators use a jack unit which includes a plunger, and a cylinder made from steel pipe or steel tubing. When the required lift or vertical travel of the elevator exceeds approximately twenty feet, the cylinder and plunger are shippped to the job site in sections, which sections are then assembled.
The cylinder sections are assembled, using a cylinder joint construction, such as shown in my copending application Ser. No. 928,636, filed July 27, 1978, now U.S. Pat. No. 4,219,226, which is assigned to the same assignee as the present application. It is important that the ends of the sections to be coupled be protected from damage during shipment. Further, the shipping protection must provide moisture seals to prevent moisture from entering the inside of the cylinder sections where it may rust and corrode threads and other machined areas of the cylinder head, cylinder joints, plunger joints, and the like, which must be maintained absolutely clean and free of corrosion for proper field assembly, and proper functioning after assembly. A caulk compound is conventionally used to provide moisture seals during shipment, but this practice requires extensive cleaning of the caulked parts in the field.
Finally, it would be desirable to provide shipping protection for the cylinder and plunger sections, which is quickly and easily applied, removed, and returned to the factory for reuse.